Amino acid synthesis activated methyl cycle

Glycolysis Citric acid cycle -oxidation of fatty acids Hexosemonophosphate shunt Oxidative phosphorylation Fatty acid synthesis Pyrimidine synthesis Purine synthesis Amino acid activation Methylation and metabolism of single carbon compounds... 

For the synthesis of the AMT ester (VIII.151), bromide (VIII. 156)-HBr was condensed in situ with 4-aminobenzoic acid and the product, 4-amino-4-deoxypteroic acid (APA), was treated directly with a mixture of formic and acetic acid to obtain the W °-formyl derivative (FmAPA, 65% yield) [292]. Condensation of FmAPA with y-r-butyl a-methyl L-glutamate to form the diester (VIII. 155) was accomplished in 82% yield by a modified mixed anhydride procedure involving four cycles of in situ carboxyl group reactivation. Hydrolysis of the methyl ester and W -formyl group at the same time with NaOH proved impossible as a result of an unforeseen loss of the y-t-butyl ester. When the a-methyl ester was first removed under mild conditions with Ba(0H)2, however, the relatively stable V -formyl derivative (VIII.154) was isolated satisfactorily in 79% yield. Subsequent cleavage of the W -formyl group was then accomplished by carefully controlled hydrolysis in 0.25 M NaOH (1.75 h at 25 °C). In an alternative synthesis, FmAPA was activated by reaction with bis(4-nitrophenyl) carbonate to obtain the corresponding... 

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